Does anybody have a solution for round stuff rolling/falling out when you open the hatch? Cargo net or barrier of some sort? We’ve had jars, melons and such breakage.
There was a thread I read, someone put a rubber lip (adhesive type molding piece or rubber weather strip will do the job) on the edge of the deck. But that was a small lip, that probably won't prevent a heavy and large round object like melons from falling off the edge, especially if your car is parked on a steep-sloped road/driveway. I would think your best solution is to either use a cargo net or a trunk organizer like shown in the photo. I use a foldable trunk organizer similar to the one in the photo. If you go for the cargo net, you will have to figure out how to install the attachment point on PP. This thread may help you: Tie down hooks and cargo net hooks in Prius Prime | PriusChat
Maybe I'm just too thrifty, but I just use a couple of right-sized cardboard boxes to contain objects that have a tendency to roll or skid around.
I’ve found the all weather mats are much more “sticky” than the carpet, so they help keep things from falling out as much. I also got a a trunk organizer. If you use the hatch cover, be careful of the height—most of the organizers are too tall. The one I got isn’t available anymore, but this one should be perfect: Rola 59001 M.O.V.E. Rigid-Base Trunk Organizer, Customizable Storage, Removable (Black), 38" Interior Organizer
Medium Mixing Tub-26100 - The Home Depot I currently keep two of these side by side in back. I like to hike on dirty (no muddy) trails and also like to be able to take all the little stuff out in one or two carrys. For you maybe duffle bags with the main shoulder strap semi-snug around the rear seat head rest to keep fragile items semi-secure to the rear seat backs, and also use the duffle bag to haul the items into the house.
Weather mat works for me. You can see a 1.5 -2" lip. Image is the Prius being installed with a 2" hitch and 1.5" lift kit.